Internal combustion engine



Aug. 10, 1937. w. R. GRlswoLD INTERNAL COMBUSTION ENGINE Filed July 22, 1953 2 Sheets-Sheet 1 M. m m De m H N Aug. 10, 1937. w. R. GRlswoLD INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 2 F'ld July 22, 1933 Patented Aug. 10, 1937 UNITED STATES PATENT OFFICE 2,089,203 j INTERNAL coMBUs'rloN ENGINE Application July-,galega seal No. 681,685

ssclaims. (cl. 12s-9o) This invention relates to internal .combustion engines and particularly tothevvalveoperating mechanism thereof.

- Automobile engineers are constantly striving to eliminate noisefrom the various mechanisms of the motor vehicle. One of the most troublesome parts of the vehicle'in this respect is the valve mechanism of the engine, principally be'- cause of the expansion and contraction of the parts of the engine in connectionwith which the valve mechanism. is mounted, and partly because of the Wear that necessarily takes place in the operation of the parts. i

The conventional Valve mechanism includes a poppet Valve and: a cam shaft for operating it. When the valve is closed there is preferably very slight clearance somewhere between Athe cam shaft and the valve stem, or at least there should be no riding ofthe valve stem on the cam shaft because in that case the valve rwould not be fully closed. A leaky valve `would soon burn or there would be a loss of power due to lack of compression.

v But if'there is too much clearance the valve operating mechanism will be noisy due to the clearance being taken up suddenly.

In most engines there is'provision for adjustment between the cam shaft and the valve stem so that a minimum of clearance may be provided forybut when this adjustment is made at agiven temperature of the engine the clearance will increase or decrease as the engine becomes hotter or cooler and then a noisy mechanism results or the valves will be caused to ride.

In some cases elaborate mechanisms have been provided for automatically taking up this valve mechanism clearance without at the same time causing the valves to ride, and the present invention is concerned with this problem.. One 40 of its objects is to provide such automatic takeup mechanism in simple form, in compact arrangement, easily assembled, easily accessible, and with the thought of insuring automatic adjustment over a fairly wide range. j 45 Another object of the invention is to provide a valve operating mechanism of this character which will not only adjust the clearance between the cam shaft and the valve butin which the operating part between the cam shaft and the 50 valve will readily adapt itself to the cam surface.

Another object of the invention is to so design the various parts of the mechanism that in commercial manufacture several parts may be sepa- 55 rately assembled into what may be termed subassemblies and then the whole brought litogetherv for convenient assembly on the engine itself with the parts in accessible position for inspection and adjustment.

Another object of the invention is to provide in a mechanism of this character for the arrangement of the regulator or adjusting mechanism on the stationary part of the engine where it may be easily inspected in operation and accessible for adjustment or removal and replace- 10 ment. v y

Another object of the invention is to provide automatic adjusting mechanism for Valve operating elements with means for dampening vibrations occurring therein. A15

Other objects of the invention will appear from the following description taken in connection with the drawings, which form a part of this specification, and in which:

Fig. 1 is a vertical sectional view of an engine having valve operating mechanism embodying the invention;

Fig. 2 is a sectional view taken on line 2 2 of Fig. 3 further illustrating the valve operating mechanism shown in Fig. 1;

Fig. 3 is a fragmentary sectional view of the same taken on line 3 3 of Fig. 2;

Fig. 4 is a sectional view on line 4-4 of Fig. 3;

Fig. 5 is a perspective View of one of the cam regulator structures which controls the position of the rocker lever fulcrum;

Fig. 6 is a sectional view taken on line 6-6 of Fig. 1, illustrating the aligned relation of the bearing points for the rocker lever;

Fig. '7 is a View similar to Fig. 2, showing 5 another form of the invention, the section being f on the line lI--l of Fig. 8;

Fig. 8 is a sectional View substantially on the line 8--8 of Fig. 7, and

Fig. 9 is a perspective view of the support for 40 the regulating mechanism, shown in Figs. 7 and 8.

Referring to the drawings, I IJ represents the crank case' of an internal combustion engine upon which is secured a cylinder block II having a head block I2 mounted thereon. Within each cylinder is a piston I3 which is connected by a rod I4 with the crank shaft I5.

As the cylinders and associated mechanisms are similar, a description of one of the units will suiiice for all. The head block is formed with a chamber I6 which overlies an end portion of the cylinder and communicates with a passage I'l in the cylinder casting. The passage I'I may be for either the inlet or the exhaust. A valve I8 5 5 is provided with a stem portion arranged to be reciprocated in a bearing sleeve I9 carried by the cylinder casting and the head portion of the valve is arranged to open 'or close the port between the chamber i6 and the passage l1. One

end of a coil spring 2D engages the cylinder casting andthe other end thereof bears against a retainer-2| which is fixed to the valve stem in the usual manner. A tappet 22 is slidably mounted 10 in a bearing 23 extending through a wall of the crank case, such tappet forming a continuation of the valve stem. The valve stern anditsjassociated tappet may be referred to herein as the valve. A cam shaft 24 extends longitudinally ofthe crank case and, in this instance, is arranged below the valves and at one sidefthereof.. -A rocker arm or lever is arranged between'the valve unitary structure which canbe readily attached to and're'rnovedfrom the engine and I also propose to arrangelthe regulator mechanism Ain a relation whereby' it is v"readily accessible either j when the unit structurei'isattaehed to or removed from the engine. To this end,'the rocker levers are arranged'to extend throughan opening 28in a side wall 'of the crank case so Vthat the journaled or fulcrumed portio'nfthereof lcan be'carried in af'ho'using 29 which is detachably secured against'the outer wallfof the crank case by means of suitable studs or bolts 29.V The housing 'isfformedwith a pair of vspaced walls 39 and 3l, the upper' one of which has upstanding bearing brackets 32 to support a 'shaft '33 which extends longitudinally ofthe engine. A removable cover l34 encloses the shaft'and Aits bearing brackets, such cover being retained in position by bolts 35 which extend into the brack- Y ets and engage recesses '36' in the shaftto prevent endwise movement'thereofjV Y Y The roekei` lever 254 is'fulc'rumed upon a bearing member 36 which 'in' turn-vis carriedV by a carrier 31 which is shown in the forrnof a'cylindrical pin'passingidiametricallytlirough an opening in the'bearing member-36'. The lower portion 38 of the carrier pin`31 is of less diameter than the upper portion 39 thereof; thus forming a shoulder 49 which bears against thebearing member 36, as shown particularly in Fig. 2. The

hub 4l of the rocker lever 25r surrounds the bearing member 36 and is provided with slots 42 and,

43 through which the pin 31' passesfand which permit the rocker lever to rock on thebearing 36 in the operation of the mechanism. The upper end 39 of theY pin 31 has flat sides 44 which bear against the side'face's of the slot 43, thus providing a greater bearing surface between the rocker lever and the pin.

'Ihe carrier pin 31 is mounted in the housing 29 in openings 45 and 46 therein, and the lower end of the pin is provided ywith a flat face 41 to permit oil to escape'from the bottom of the recess formedby Vthe opening 45.

lThus it will be seen that the rocker lever or rocker levers are carried by the housing 29 and they may be assembled in the housing and then the housing and the rocker levers may be assembled on the engine as a unit. For the purpose of holding the rocker levers against undue turning in the housing before assembly on the engine, each of the rocker levers 25 is provided with a lug'48 `extending fromthe hub 4| and adapted to operate between separated ribs 49 formed in the housing. Sucient clearance is provided between the lug 48 and the adjacent ribs so thatthe rocker levers will have slight movement about the axis of the pin 31 for the purpose ofpermittingthe rocker lever to prop- 'erly position itself relative to the cam shaft.

Therefore; since the rocker lever 25 is supported inthe housing 29 on the axis of the pin 31, and since theroller 21 and the bearing face 28 :are aligned with the carrier pin 31, the roller will automatically nd its bearing on the `cam face and there willbe no binding or uneven wearing of the roller or cam. I f f Y In the form of the invention shown'in Figs. 1 to 6 inclusive, the carrier 31 is so supported thatin the operation' of the-mechanism'fthe carrier will be moved laterally 'er vibrated-so Ithat it may co-operate withthe regulating or adjusting mechanism which .positions it axially in its support. 'Thus the carrier pin 31 is mounted in the housing 29 not only for-axial movement in the openings 45'and 46 but also for slight lateral movement` therein; Thus, as indicated on the drawings in Fig. 2, thereis diametral clearance" of from two to ve thousandths of an inch between the cylindrical surfaces ofthe portions l 38 and 39 of the pin 31 and the openings or recesses 45, 46, respectively,'of the housing. This ismorelthan enough clearance for the normal axial movement of the pin for'adjustment of the'fulcrum of the rocker lever 25, so that when the cam 9 of 'the cam shaft 24'reaches a position where it starts to'raisefthe rocker lever 25, it also ten-ds to move the lever'endwise or -towards the left in Fig. 2 and this moves the pin 31 laterally so that the clearance is all on the right hand side thereof. Then as the roller 21 Vrolls down the other side of the cam 9, under urging ofthe valve'spring 20, the rocker lever 25 is urged toward the right in Fig. 2and'the'pin 31 is moved slightlyto the right so that all of the clearance is then on the left-hand side of the pin. In' the rapid rotation -of the cam shaft 24 this setsl up aV lateral vibration'of the pin 31 and facilitates the operation of the regulating mechanism. 'Y

The regulating or adjusting mechanism for the fulcrum ofth'e rocker lever 25 is mounted on a stationary part of the engine and as shown, it is supported on the shaft l33 which is mounted in the brackets 32 of the housing 29. This regulating mechanism may be assembled Separately and the assembly is then threaded on tothe shaft 33. Two of these mechanisms are shown in Fig. 3, one on either side of the bracket 32.

They arev alike except that they are reversed'relative to the bracket 32.

As assembled in place on' the shaft 33 the regulating or adjusting mechanism comprises a cam 55 adapted to rotate on the shaft 33 immediate'- ly above the pin 31. Its periphery is in contact with the upper end of the pin which carries the rocker arm, so that therdirectionof vibrating movement of the contacting surface of the pin, is tangent to the surface of the cam.` The cam is Shown as slightly offset relative to the center of the pin, however, it can be centrally located if desired. The periphery of this cam is preferably of involute form as shownv particularly in Figs. 1 and 2 so that its rotation in one direction on the shaft will tend to push the pin 31 downwardly in Fig. 2 and its rotation in the reverse direction Will permit the pin tomove upwardly under pressure of the valve spring 2l).

A stamped metal casing 56, of cylindrical form, and having its outer end opened and its inner end partly closed by a flange 58, is secured in somewhat offset relation to the 'side of the cam 55. The oifset is obtained by a portion of the flange 53 being extended as shown at 59 and formed with a lip 60 which is'the part of the casing riveted or xed to the cam as by the rivets 51.

Within the cylindrical casing 56 and keyedV upon the shaft 33 is a sleeve 6|. VAt one end this sleeve abuts against the bracket 32 and at the other end against the cam 55. A spring 62 surrounds the shaft 33 on the opposite side of the cam 55 and a cotter pin 63 extends through the shaft and retains the spring 62 in somewhat comp-ressed condition against the cam, thus holdingy the parts in place and damping any lateral vibrating action of the cam.

YCoiled about a portion of the sleeve 6| and within the casing 55 is a spring 64 having one of its ends secured in a slot in the sleeve 6| as shown at 55 and its other end secured in a slot in the casing 56 as shown at 66, particularly in Fig. 5. The spring is wound under tension so that it tends to lrotate the cam 55 on its axis, the sleeve 6l being keyed to the shaft 33 which is prevented from turning by reason of the bolt 35. This tendency of the cam 55 to rotate is in a clockwise direction in Fig. 2 so that the cam tends to push the carrier pin 31 downwardly and thus tends to take up clearance between the cam shaft 25 and the engine valve. Incase the clearance has been taken up to such an extent that there is a tendency on the'part of the engine valve to ride, the valve spring 20 willtend to push thel carrier pin 31- upwardly with con-r siderable force and'this willv be resisted by the cam 55. To prevent this riding action the retraction of the cam 55 is necessary and this is facilitated by the vibratory action of the pinA 31 in a direction tangent to the cam 55 as above pointed out. Thus, with each rotation of the cam shaft 25 the upper end of the pin 31 is moved laterally from one side to the other and back again, taking upv the clearance between it and its support, rst on one side and then onv the other. It is this'relative movement between the cam 55 and that part of the pin 31 with which it contacts that accomplishes the retraction of the cam against its spring 64 under these conditions. f

It should be pointed out that the spring 64 is in the form of a flat watch spring and only two or three coils are illustrated. This is a desirable form of spring but in practice six or eight coils are used, the lesser number of` coils beingillustrated in order to make the showing clearer.

For assembling the regulator oif of the shaft 33 the sleeve Si. is made'to loosely t within the flange 58 of the casing and it is formed with a iiange 61 intermediate its ends, which flange 61 is extended radially at one point to form an arm E8 which, when the sleeve 6| is `arranged within the flange 58, will extend slightly beyond the extension 59 of the casing 56. The arm 68 and the extension59 thereby form a stop means to limit 75 relative rotation ofzthe 'sleeve BI relative to the cam 55 and housing 55, in both directions.' In Fig. the arm 68 is shown as resting against the extension 59, and in Fig. 4 the arm 68 is shown in full lines in its intermediate position in which the sleeve is operative relative to the cani 55, and in dotted lines in its two extreme positions resting against the extension 55.

' The extension 5S of the casing 56 is preferably formed by punching out a part of the flange 58 and this forms an opening through that iiange through which the sleeve 'l may be assembled with its flange 61 and arm 6B arranged between the flange 58 and the cam 55. Thus the parts may be assembled as shown in Fig. 5 with the cam 55, its integral casing 55, the sleeve 5|, and the spring 54 assembled with relation to eachother. This assembly may be threaded onto the shaft 33 with 'the open end of the casing 55 adjacent the bracket 32 whereby the latter retains the spring within the casing, and with the spring 62 yieldingly holding the parts in place.

In the form of the invention shown in Figs. 7, 8 and 9 the crank case l5, its opening 28, the valve means 22, the rocker lever 25, its roller 21, the bearing member 35, the lug :33 and ribs 49 may be the same as in the other construction. The housing 29 is substantially the same except that the upper part thereof is formed with an opening 1U through which the openings 45 and 55' may be drilled, a cover 1l being provided for the opening it, and except for an extension 12 which may be said to replace the brackets 32 of the other construction. The extension 12 is formed with an opening 'i3 through which the regulator assembly is assembled within the housing, and a cover 1li forms a support for the regulator mechanism, being secured in place by bolts 15. A single cover is shown as supporting two of the operating mechanisms but it may support more or less of them.

In this form of the invention the relative vibration between the carrier pin 31 and the cam 55 is attained, not by yproviding clearance between the pin 31 and its support, but byv slight oscillation of the pin 3l' during the operation of the mechanism and by offsetting the cam 55 to a greater extent than shown in the other form. Thus the clearance at 45 and 35' in this construction, is enough only to insure free axial movement of the pin 31 in its adjusting or regulating operation, and the pin itself is oscillated slightly by the rotation of the cam shaft 24. This oscillation of the pin may be accomplished in any desirable way but as herein shown the cylindrical segment of the cain 9, upon which the roller 21 operates, is formed with waves 16, (shown greatly exaggerated for clearness) as shown in Fig. '1, so that as the roller i?? follows the cam shaft there is a tendency for it to move first to one side and then to the other, of the cam, and of course carrying with it the free end of the lever 25. This lateral movement of the rocker lever 25 gives the pin 31 a slight oscillating movement. The cam 55 is shown as oifset relative to the axis of the pin 31 and consequently this oscillating movement of the pin causes a tangential relative movement between the upper enlarged end 11 ofthe pin and the cam 55. This relative movement facilitates retraction of the cam against its spring when there is a tendency of the engine valve to ride, as above pointed out.

The regulating mechanism is the same in all particulars as that shown in the other form, but its supporting shaft is arranged laterally of the cam shaft 213, instead of parallel thereto, and

It will be understood that various forms of the Y invention other than those described above may be used without departing from the spirit or scope of the invention.

What I' claim and desire to secure by Letters Patent is:

1. In a valve operating mechanism, the combination of a valve operating member, a support therefor to provide for its normal rocking action in operating the valve, means provided for additional vibratory action of said member during operation, and a spring actuated cam device directly pivoted upon said support for adjusting the position of said member to take up clearance, said vibratory action assisting in the operation of said cam device.

Y2. A take-up mechanism including a shaft, a Y

cam rotatably mounted on said shaft, a sleeve mounted upon and keyed to said shaft adjacent said cam, a coil spring having one end connected to the cam and the other end'connected to the sleeve, and stop means between the parts to limit the relative rotary movement in both directions between the cam and the sleeve, said cam, sleeve and spring being self-contained for assembly upon or disassembly from said shaft.

3. A take-up mechanism including a shaft, a cam element on the shaft, a second element on the shaft, a coil spring connecting said elements tending to turn one relative to the other, stop means between the elements to limit. the range of relative rotary movement between them, and

means for securing one of said elements againstY 4. A take-up mechanism including a shaft, aI

cam element on the shaft, a second element on the shaft, a coil spring connecting said elements tending to turn one relative to the other, stop means between the elements to limit the range of relative rotary movement between them, and means for securing one of said elements against rotation on the shaft, said elements and spring being adapted for assembly upon and disassembly from said shaft as a unit, and said stop means retaining the elements against undue relative movement when the unit is disassembled from the shaft.

5. In a valve operating mechanism, the combination of supporting means, a rocker arm mounted in said supporting means so that it may rock in operating the valve and so that it may have slight movement lengthwise, and a cam device mounted directly on the supporting means and acting against said rocker arm to adjust the rocker arm for clearance take-up.

6. In a valve operating mechanism, the combination of a rocker arm, a bearing member therefor, a carrier passing laterally through the bearing member, and a carn member mounted independently of said carrier and operating directly against said carrier to move the latter to thereby adjust the axis of the bearing member, for the purpose set forth.

'7.V In a valve operating mechanism, the combination of a part to be adjusted for clearance takeup, and `a regulator therefor comprising a supporting shaft, a cam: rotatable on the shaft, a part keyed to the shaft, and a coil spring having one end connected to said cam and the other end connected to the part keyed to the shaft.

8. In a valve operating mechanism, the combination of a 'cam shaft, a valve, a rocker arm adapted to be rocked by the cam shaft and to operatethe valve when so rocked, and means for supporting'the rocker arm so that it may move laterally to find its correct operating position on the cam shaft.

9. In a valve operating mechanism, the combination ofa cam shaft, a valve, a rocker arm adapted to be rocked by the cam shaft and to operate thev valve when so rocked, means for supporting th'e rocker Varm so that it may move laterally to find its correct operating position on the cam shaft, and means for limiting said lateral movement.

10. In a valve operating mechanism, the combination of a cam shaft, a valve, a rocker arm adapted to be rocked by the cam shaft and to operate the valve when so rocked, and means for Y described.

12. In a valve ltake-up mechanism, the combinationy of a valve operating part adjustably mounted to take up clearance, a cam part mounted on a; stationary support and adapted to adjust' said valve .operating part, one of said partsbeing so mounted as to vibrate slightly during operation in addition toits normal functional movement, and a spring for operating said cam 'part in co-operation with said vibratory movement.

13. Valve operating mechanism comprising a rocker lever, a bearing Aon which the rocker lever is mounted, a movable carrier means, means for automatically regulating the position of the carrier including an involute cam engaging with the carrier means, and vibration damping means associated with the cam.

' 14. Valve operating mechanism having a rocker lever with shiftable fulcrum means, regulator mechanism for the fulcrum means comprising a xed shaft, a sleeve fixed on the shaft, an involute cam rotatable on the shaft engageable with the fulcrum means, spring means between the sleeve and the cam urging the cam into wedging relation with the fulcrum means, and a Vcoil spring on the shaft bearing against said the casing.

1.6.` Valve operating mechanism comprising a rockerlever adapted to engage a cam and a valve, a bearing on which'said rocker lever is mounted,

an axially slidable and rotatably mounted carrier on which the bearing is carried, and. regulator means 'engaging the carrier to automatically maintain it in Aposition holding the rocker lever in .engagement with the valve.

517;. Va1ve operating mechanism comprising a frocker .leyerffor operating a valve, said lever having a-.dametrically slotted hubportion, a cy- -lindricalgmember mounted to move axially, a

bearing in said hub portion and'carried by said member, said member extending through the bearingand the slot'in the hub portion of the rocker lever, and means engaging the member to regulate the axial position thereof.

18. Valve operating mechanism comprising a rocker lever for operating a valve, said lever having a hub portion with diametric slots therein, a cylindrical member mounted to move axially and having diametric flat portions, and a bearing carried on the member and on which the hub of the lever is mounted, the member extending through the bearing and the slotted portions of the hub and having the flat portions thereof bearing against the hub walls forming one of the slots.

19. In an engine, a casing having a support With spaced ribs, al pin slidable axially and rotatably mounted in the support, a bearing mounted on th-e pin, a rocker lever fulcrumed on the bearing, and an extension on the rocker lever extending between the ribs of the casing, said ribs and extension being arranged to limit the lateral movement of the rocker lever.

20. Valve operating mechanism comprising a rocker lever for operating a valve, a bearing on which the rocker lever is mounted, carrier means for the bearing movable in a straight liney to vary the position thereof, and regulator means engaging the carrier means to automatically position the bearing in a position whereby the lever is maintained in engagement with the valve.

21. Valve operating mechanism comprising a rocker lever having a hub portion, a movable carrier, a bearing carried by the carrier, the hub portion of the lever being mounted on the bearing, and a spring operated cam having an involute peripheral surface directly engaging one end of the carrier.

22. Valve operating mechanism comprising a rocker lever, an axially movable cylindrical carrier member, a bearing carried by the member, said lever being pivotally mounted on the bearing, a cam having an involute peripheral surface engaging one end of the carrier member, and spring means associated to turn the cam relative to the carrier member and thereby maintain lthe bearing in a desired position.

23. Valve operating mechanism comprising a rocker lever adapted to be rocked to operate a valve, a bearing on which the rocker lever is pivotally mounted, an axially slidable carrier member, and a pressure actuated cam engaging an end of the carrier member, said cam being mounted in alignment With the carrier.

24. Valve operating mechanism comprising a rocker lever adapted to be rocked to operate a valve, a movable fulcrum means for the rocker lever, a cam directly engaging the fulcrum means for regulating its position, a shaft on which said cam is rotatably mounted, a spring housing secured to one side o f the cam, a member` fixed to the shaft, and a spring in the.housing,said spring being securedV at, one end to the housing and vsecured at the lother end to the member fixed to the shaft, said spring exerting a force to move the camin a direction shifting thefulcrum means vto maintain constant engagement of therocker lever with the valve.

25. Valve operating mechanism comprisingA a rocker lever adaptedr to. be tripped 'to` operate a valve, a movably mounted fulcrum means for the rocker lever, a cam directly'engaging the fulcrum means for regulating its position, axed shaft on which the, cam is rotatably mounted,ra.sleeve iixcd to the cam adjacent thereto, said sleeve hav ving an arm extending 4therefrom, ,anspring housing surroundingA the sleeve and having va neck portionlxedfto oneside of the cam, a/coil spring in the housing, one end of the spring being fixed to the sleeve and the other end of the spring being xed tothe housing, said arm being in the path of rotation of the housing neck to limit the rotation of the cam relative to the sleeve.

26. In a valve operating mechanism, the combination with a cam shaft and a rocker lever operated thereby, of a. pivoted carrier for the fulcrum of the rocker lever, a take-up cam operating in contact with, and in offset relation tothe axis of, the carrier, and means for vibrating the carrier about its axis.

27. In a valve take-up mechanism, the combination of a valve operating part, means for adjustably mounting said part to take up clearance, a cam supported by a stationary part with the face of said cam contacting the mounting of said valve operating part to adjust said valve operating part, s aid mounting means and said cam being separate elements, and a spring having a part connected to the cam for operating said cam.

28. In an internal combustion engine, the combination with a valve and a rocker arm having a movable support, of a clearance take-up cam mounted on a stationary part of the engine and having a, peripheral cam surface in contact with said movable support, said movable support and said cam being separate elements, and means for Vibrating said movable support with relation to the cam surface tangent to said surface.

29. A take-up mechanism comprising two elements, one a cam and the other a sleeve, one of said elements being prepared for pivotal mounting and the other for keyed mounting upon a shaft, a spring having its ends connected to said elements respectively, and stop means between the elements to limit the relative rotary movement thereof, whereby the two elements, the spring and the stop means are self-contained for assembly upon or disassembly from a shaft.

30. A take-up mechanism comprising a cam prepared for pivotal mounting, a sleeve prepared for keyed mounting upon a shaft, a coil spring `having one end connected to the cam and the other end connected to the sleeve, and stop means between the cam and sleeve to limit the relative rotary movement thereof, whereby the three elements are self-contained for assembly upon or disassembly from a shaft.

31. The combination with a valve operating means to be adjusted, of an automatic adjusting mechanism including a shaft, a cam rotatably mounted on said shaft to adjust the operating means, a sleeve mounted upon and keyed to said shaft adjacent said cam, a coil spring having one end connected to the cam and the other end connected to the sleeve, and stop means'between the parts to limit the relative rotary movement in both directions between the cam and the sleeve.

32. In aV valve operating mechanism, the 'combination with a support and a cam shaft anda rocker lever mounted on the support and the rockery lever operated by the cam shaft, of a clearance take-up device comprising a springoperated cam controlling the position of said rocker lever and oscillatively mounted on said support independently of the rockerlever.

33. In an engine valve mechanism, the combination with a cam shaft, a rocker arm having a part in contact with a cam on said shaft and a part foroperating a valve, and a valve operated by said rocker arm, of a support for said cam shaft and said rocker arm, means for mounting said rocker arm on said support, said mounting means comprising abearing `which allows the rocker arm! to befrockedgbyv-the cam shaft to thereby operate the valve, said mounting means 'beingsoconstructed that the rocker arma'may have a: slight bodily vmovement in addition'to the and operating upon said rocker arm in'coopera.- 1

tion with the bodily movement thereof caused by the-operation of the cam shaft, toadjust the rocking axis of the rocker arm during the operation of the mechanism; L Y 1 WALTER y R. GRISWOLD. 

